Lennox LGM Series Manual page 46

RT16
RETURN
AIR SENSOR
RT17
OUTDOOR AIR SENSOR (ON HIGH
AND STANDARD EFFICIENCY UNITS
EQUIPPED WITH TUBE/FIN COIL)
I-Gravity Exhaust Dampers
LAGEDH03/15 dampers (figure 38) are used in downflow
and horizontal air discharge applications. Horizontal gravi­
ty exhaust dampers are installed in the return air plenum .
The dampers must be used any time an economizer or
power exhaust fans are applied to LGM units.
Gravity exhaust dampers allow exhaust air to be dis­
charged from the system when an economizer and/or pow­
er exhaust is operating. Gravity exhaust dampers also pre­
vent outdoor air infiltration during unit off cycle. See
installation instructions for more detail.
GED AND PEF
EXHAUST FAN ASSEMBLY
EXHAUST DAMPERS
FIGURE 38
SENSOR LOCATION
FIN/TUBE UNIT SHOWN
RT6
DISCHARGE AIR
SENSOR
PEF POWER
(ORDERED SEPARATELY)
GED GRAVITY
FIGURE 37
J-LAPEF Power Exhaust Fans
Power exhaust fans are used in downflow applications on­
ly. Fan requires optional down flow gravity exhaust
dampers and LAREMD economizer. Power exhaust fans
provide exhaust air pressure relief and also run when return
air dampers are closed and supply air blowers are operat­
ing. Figure 39 shows the location of the LAPEF. See instal­
lation instructions for more detail.
POWER EXHAUST FAN
Page 46
RT17
OUTDOOR AIR SENSOR (ON
ULTRA HIGH EFFICIENCY UNITS
AND UNITS EQUIPPED WITH AN
ALL-ALUMINUM COIL; SECURED
TO INSIDE OF CORNER MULLION)
P18/P24 RETURN AIR
OPENING
POWER EXHAUST
FAN ASSEMBLY
FIGURE 39